In 1916 Bertrand Russell was prosecuted and fined for publishing (in defence of a conscientious objector) ‘statements likely to prejudice the recruiting and discipline of His Majesty’s forces.’ He was almost immediately afterwards dismissed from his Lectureship at Trinity College, Cambridge, by the College Council. This expulsion provoked a storm of protest and the true facts of the case became obscured by misconceptions, prejudices and uninformed gossip, to the discredit of the College. In 1942, therefore G. H. Hardy the mathematician printed for private circulation to another generation of Fellows at Trinity a full account of the incident in an attempt to explain what really happened. This is now made public. Besides provoking an authoritative record of a celebrated but misinterpreted episode in Russell’s eventful academic career, this document contains interesting evidence about attitudes to pacifism in the First World War and in particular about the sympathies of such distinguished colleagues and contemporaries of Russell as Cornford, Housman, McTaggart and Whitehead.